Reported hate crimes with racial or ethnic bias jumped the day after President Trump won the 2016 election, from 10 to 27, according to an analysis of FBI hate crime statistics by The Washington Post. There were more reported hate crimes on Nov. 9 than any other day in 2016, and the daily number of such incidents exceeded the level on Election Day for the next 10 days.

FBI data collected since the early 1990s show that reports of hate crimes typically spike during election years, according to a study by the Center for the Study of Hate and Extremism at California State University at San Bernardino. There was a 21 percent increase in reported hate crimes the day after Barack Obama won his first election in 2008, though hate crime reports remained relatively flat for the rest of the year.

It’s unclear why election years bring an increase in reported hate crimes, particularly in the days following the election of our last two presidents. It could be that people frustrated or energized by the election results take out those emotions on people who are different than them. Or, given that hate crimes are notoriously underreported, the election could embolden victims to report the crimes against them.

New York City police have one of the largest hate crime units in the country, but incident reports from the department offer few clues about what drives the election-year trend. On Nov. 1, 2016, police filed a report about a 63-year-old African American woman in the Queens borough of New York who found anti-black statements written on her door as she was coming home. And on Nov. 18 of that year, a report was filed alleging two African American men approached a white woman and man in Manhattan and yelled anti-white statements, before striking the 61-year-old man with a skateboard. It’s unclear whether these incidents were influenced by the election.

But a conspiracy case in Kansas shows how elections could potentially influence people to turn their political views into criminal acts. A trial began Thursday for three white men accused of plotting to bomb a mosque and a building where many Somali Muslim refugees live in southwest Kansas. Prosecutors say the men planned to detonate the bombs the day after the 2016 election.

During opening statements, Jim Pratt, attorney for defendant Patrick Stein, said his client had been influenced by the charged discourse of the campaign, calling Muslims “cockroaches.” The defendants have been charged with conspiracy to use a weapon of mass destruction, not a hate crime. But according to a criminal complaint, Stein was recorded by an FBI informant saying, “The only good Muslim is a dead Muslim,” and “If you’re a Muslim I’m going to enjoy shooting you in the head.”

Defense attorneys sought — unsuccessfully — to expand the jury pool to an area of rural Kansas where people were more likely to have voted for Donald Trump.

Researchers have attempted to categorize hate crimes in hopes of understanding what makes them manifest. Jack Levin and Jack McDevitt at Northeastern University published a study detailing several types of hate crimes, including retaliatory hate crimes that are provoked by a previous perceived hate crime or act of terrorism. Incidents like the Rodney King verdict in 1992 and the 9/11 attacks both saw dramatic increases in hate crime violence following the event.

“There’s no one single accelerant for a hate crime although, at particular times, one accelerant will override like a terrorist attack,” said Brian Levin, who runs the Center for the Study of Hate and Extremism at CSUSB. “That being said, the basic truth that a catalytic event can correlate to an increase in hate crime is quite stark.”

Sussing out the cause of the spike in reported crimes is even more difficult, because the crimes are notoriously underreported, experts say, andthe data are spotty, at best.

Congress passed the Hate Crime Statistics Act in 1990, which required the attorney general to collect data “about crimes that manifest evidence of prejudice based on race, religion, sexual orientation, or ethnicity.” The FBI was tasked with implementation and this program added hate crimes to its uniform crime reporting unit.

However, of the 10,000-plus city police agencies that submitted incidents, 14.5 percent reported at least one hate crime, according to a Post analysis. Hawaii doesn’t provide hate crime statistics, leaving the entire state unaccounted for. And the data account for violent hate crimes only, not hate speech incidents in person or online.

Crime data are often reflective of the agency that collects the information, and it’s not always clear what fuels increases or decreases in crime. Hate crime data are especially difficult to understand because crimes are largely affected by demographics, population and size of the police force.

Aaron WilliamsAaron Williams is a reporter who specializes in data analysis and visualization for The Washington Post. Before joining The Post, he covered housing, campaign finance, police and local politics for the San Francisco Chronicle and the Center for Investigative Reporting. Follow

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